Scirocco Central

Hi all. New to forum but long time owner.
I a looking to update the Bluetooth module so that all phones work.
Radio is an RNS510 which will also need updating soon.
Problem is which bluetooth unit. They all have different codes.
Can you help me understand the code and what it means.
Currently looking at
3C8 035 730 E
7PC 035 730 M
7P6 035 730M
There will be more to check
Can anyone explain the first 3 letter/number combos and also the last letter.

Thanks

Can anyone tell me which is the newest part number and how they can tell? (they are all Bluetooth units that are under the seat)

3C8 035 730 E
7PC 035 730 M
7P6 035 730M